The transparent conductive film is a sheet having a good electrical conductivity and a high transmittance in the visible light. Currently, the transparent conducting films have been widely used in the fields such as flat panel displays, photovoltaic devices, touch panels, and electromagnetic shielding, thus having a very broad market space.
ITO has dominated the market of the transparent conductive film. In most practical applications, such as touch screens, the former often requires exposure, imaging, etching and cleaning processes to pattern the transparent conductive film before use. Comparing to that, using a printing method or a silver salt method to form a metal grids directly on the specified region of the substrate can omit the patterning process, thus it has some advantages such as low pollution, low cost, etc. The patterned flexible transparent conductive films with excellent performance have been acquired using printing method by Japanese companies Dai Nippon Printing, Fujifilm and Gunze, as well as German company PolyIC. Among them, the film obtained by PolyIC has a graphics resolution of 15 μm, a surface square resistance of 0.4-1 Ω/sq, and a light transmittance exceeding 80%.
A transparent conductive film based on embedded patterned metal grid is disclosed, and the transparent conductive film with a PET substrate has a transmittance exceeding 87%; the transparent conductive film with a glass substrate has a transmittance exceeding 90%, and a surface square resistance less than 10 Ω/sq; especially for those having a resolution of metal lines less than 3 μm. However, in order to further reduce costs and make the touch module thinner, many touch screen manufacturers currently has pay more attention on the development of double-sided patterned transparent conductive film.
The trenches of the conventional embedded patterned transparent conductive film are formed by imprint techniques. Therefore, in order to prepare the double-sided patterned transparent conductive film, it is essential to develop a large format roll-to-roll double-sided aligned imprint technique, which, however, is currently far from mature.
Therefore, it is desire to provide a double-sided patterned transparent conductive film which can avoid alignment problems caused by double-sided imprinting.